|Carroll, Jeffery - Jeff Carroll|
|DONALDSON, JANET - Mississippi State University|
|BUNTYN, JOE - Mississippi State University|
|SCHMIDT, TY - University Of Nebraska|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 11/27/2012
Publication Date: 7/1/2013
Citation: Sanchez, N.C., Carroll, J.A., Donaldson, J.R., Buntyn, J.O., Schmidt, T.B. 2013. Circulating concentrations of non-esterified fatty acids (NEFA) as mediators of the innate immune response in cattle. Journal of Animal Science Supplement. 91(E-Suppl.2):21-22 (Abstract #58).
Technical Abstract: We previously reported that temperamental cattle have greater non-esterified fatty acid (NEFA) concentrations and an altered innate immune response compared to calm cattle. Therefore, this trial was designed to determine if increasing energy availability via a lipid infusion or bolus dextrose injection would alter the innate immune response following a lipopolysaccharide (LPS; 0.5 micrograms/kg body weight) challenge. Holstein steers (n=21; 165+/-5 kg body weight) were randomly assigned to 1 of 3 groups: saline at 0.5 mililiters/kg body weight (CON; n=7), 50% dextrose (0.5 mililiters/kg body wieght; DX, n=7) administered immediately prior to LPS to mimic peak LPS-induced glucose observed in calm cattle, or continuous lipid emulsion infusion (intralipid 20%; 0.5 mililiters/kg/h; LIP; n=7) via a jugular cannula from -1 to 6 h post-LPS. On d -1, steers were fitted with jugular cannulas and indwelling rectal temperature (RT) probes and placed into tie stalls. On d 0 blood samples were collected starting at -3 h and continuing until 8 h post-LPS. Serum was analyzed for cortisol, interferon-gamma (IFN-gamma), interleukin-6 (IL6), NEFAs, and glucose. Infusion of LIP prior to LPS administration (-1 to 0 h) resulted in a time x treatment interaction for NEFA (P<0.01) and a tendency for cortisol (P=0.06) such that NEFA and cortisol were greater in LIP than CON and DX steers. All variables increased following LPS challenge (P<0.01). Following LPS administration there was a time x treatment interaction for NEFA (P<0.01) and cortisol (P<0.01) such that NEFA remained greater while cortisol was decreased in LIP than CON and DX steers. Glucose was decreased in CON than LIP and DX steers (P=0.04) post-LPS, while the change in RT relative to baseline was less in DX than CON and LIP steers (P<0.01). Concentrations of IL6 and the change in IFNy relative to baseline were less in LIP than CON and DX steers (P<0.01), with DX having lower IL-6 than CON steers (P<0.01). To our knowledge, these are the first data to suggest that increasing circulating NEFA concentrations may modulate the innate immune response in cattle, and that the greater NEFA concentrations observed in temperamental cattle may be responsible for the altered innate immune response reported in these cattle following a LPS challenge.